Process for preparing substituted aromatic amines

ABSTRACT

A process for preparing substituted aromatic amines which comprises contacting a nucleophilic compound and a substituted aromatic azo compound in the presence of a suitable solvent system, and reacting the nucleophilic compound and the substituted aromatic azo compound in the presence of a suitable base and a controlled amount of protic material at a temperature of about 70° C. to about 200° C. in a confined reaction zone wherein the molar ratio of protic material to base is 0:1 to about 5:1. In another embodiment, the substituted aromatic amines of the invention are reductively alkylated to produce alkylated diamines or substituted derivatives thereof.

This application is a Divisional of U.S. Ser. No. 08/038,047 filed Apr.6, 1993, now U.S. Pat. No. 5,552,531 which is a Continuation-in-part ofU.S. Ser. No. 07/887,060 filed May 22, 1992, now Abandoned.

BACKGROUND OF THE INVENTION

This invention relates to the production of substituted aromatic azocompounds. In one aspect, this invention relates to the production ofsubstituted aromatic amines. In another aspect, this invention relatesto the production of 4-aminodiphenylamine (4-ADPA) or substitutedderivatives thereof. In another aspect, this invention relates to thepreparation of alkylated p-phenylenediamines or substituted derivativesthereof useful as antioxidants from the substituted aromatic amines,such as 4-ADPA or substituted derivatives thereof.

It is known to prepare substituted aromatic amines by way of anucleophilic aromatic substitution mechanism wherein an amino functionalnucleophile replaces halide. For example, it is known to prepare 4-ADPAby way of a nucleophilic aromatic substitution mechanism, wherein ananiline derivative replaces halide. This method involves preparation ofa 4-ADPA intermediate, namely 4-nitrodiphenylamine (4-NDPA) followed byreduction of the nitro moiety. The 4-NDPA is prepared by reactingp-chloronitrobenzene with an aniline derivative, such as formanilide oran alkali metal salt thereof, in the presence of an acid acceptor orneutralizing agent, such as potassium carbonate, and, optionally,utilizing a catalyst. See, for example, U.S. Pat. Nos. 4,187,248;4,683,332; 4,155,936; 4,670,595; 4,122,118; 4,614,817; 4,209,463;4,196,146; 4,187,249; 4,140,716. This method is disadvantageous in thatthe halide that is displaced is corrosive to the reactors and appears inthe waste stream and must therefore be disposed of at considerableexpense. Furthermore, use of an aniline derivative such as formanilide,and use of p-chloro-nitrobenzene, requires additional manufacturingequipment and capabilities to produce such starting materials fromaniline and nitrobenzene, respectively.

It is also known to prepare 4-ADPA from the head-to-tail coupling ofaniline. See, for example, G.B. 1,440,767 and U.S. Pat. No. 4,760,186.This method is disadvantageous in that the yield of 4-ADPA is notacceptable for a commercial process. It is also known to decarboxylate aurethane to produce 4-NDPA. See U.S. Pat. No. 3,847,990. However, suchmethod is not commercially practical in terms of cost and yield.

It is known to prepare 4-ADPA by hydrogenatingp-nitrosodiphenylhydroxylamine which can be prepared by catalyticdimerization of nitrosobenzene utilizing, as a reducing agent, aliphaticcompounds, benzene, naphthalene or ethylenically unsaturated compounds.See, for example, U.S. Pat. Nos. 4,178,315 and 4,404,401. It is alsoknown to prepare p-nitrosodiphenylamine from diphenylamine and an alkylnitrate in the presence of excess hydrogen chloride. See, for example,U.S. Pat. Nos. 4,518,803 and 4,479,008.

Aromatic amide bonds are currently formed by the reaction of an aminewith an acid chloride. This method of forming aromatic amide bonds isalso disadvantageous in that chloride is displaced which is corrosive tothe reactors, and appears in the waste stream from which it must beremoved at considerable expense. A nonhalide process which producesaromatic amide bonds in the substituted aromatic amines would eliminatethese problems.

The process of the invention is a nonhalide process for preparingsubstituted aromatic azo compounds and substituted aromatic amines andtherefore eliminates the expensive halide removal from the waste streamas well as corrosion problems caused by the halide. In addition,substituted aromatic azo compounds and substituted aromatic aminescontaining aromatic amide bonds can be prepared by the process of theinvention. Furthermore, the process of the invention is more economicalthan current commercial routes and is simpler in that, in oneembodiment, substituted aromatic amines, such as 4-ADPA or substitutedderivatives thereof, are produced directly without the need of aseparate reduction step.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a process for producingsubstituted aromatic azo compounds for use in preparing substitutedaromatic amines. It is a further object of the invention to provide aprocess for producing substituted aromatic amines for use in preparingalkylated p-phenylenediamines or substituted derivatives thereof. It isa still further object of the invention to provide a process forproducing 4-ADPA or substituted derivatives thereof for use in preparingalkylated p-phenylenediamines or substituted derivatives thereof. It isa further object of the invention to provide an efficient and economicprocess to produce 4-ADPA or substituted derivatives thereof andalkylated p-phenylenediamines that is commercially viable. It is a stillfurther object of the invention to provide a process for producingalkylated p-phenylenediamines or substituted derivatives thereof for useas antioxidants and antiozonants.

According to the invention, a process for preparing substituted aromaticazo compounds is provided which comprises contacting a nucleophiliccompound selected from the group consisting of aniline, substitutedaniline derivatives, aliphatic amines, substituted aliphatic aminederivatives and amides with an azo containing compound represented bythe formula X--R₁ --N═N--R₂ --Y or azoxy or hydrazo derivatives thereofin the presence of a suitable solvent system, and reacting thenucleophilic compound and a compound represented by the formula X--R₁--N═N--R₂ --Y or azoxy or hydrazo derivatives thereof in the presence ofa suitable base and a controlled amount of protic material at a reactiontemperature of about 10° C. to about 150° C. in a confined reactionzone, wherein the molar ratio of protic material to base is 0:1 to about5:1, wherein R₁ is an aromatic group and R₂ is selected from the groupconsisting of aliphatic and aromatic groups, and X and Y areindependently selected from the group consisting of hydrogen, halides,--NO₂, --NH₂, aryl groups, alkyl groups, alkoxy groups, sulfonategroups, --SO₃ H, --OH, --COH, COOH, --and alkyl, aryl, arylalkyl oralkylaryl groups containing at least one --NH₂ group. When R₂ is analiphatic group, X is in the meta or ortho position on R₁. When R₂ is anaromatic group, at least one of X and Y is in the meta or ortho positionon R₁ and R₂, respectively. Halides are selected from the groupconsisting of chloride, bromide and fluoride. Sulfonate groups, as usedherein, are the esters of sulfonic acids. Examples of sulfonatesinclude, but are not limited to, alkyl sulfonates, aralkyl sulfonates,aryl sulfonates, and the like. In one embodiment, the substitutedaromatic azo compound is further reacted with a nucleophilic compoundindependently selected from the group consisting of aniline, substitutedaniline derivatives, aliphatic amines, substituted aliphatic aminederivatives and amides in the presence of a suitable solvent system, asuitable base and a controlled amount of protic material at a reactiontemperature of about 70° C. to about 200° C. in a confined reactionzone, wherein the molar ratio of protic material to base is 0:1 to about5:1.

In one embodiment, a process for preparing 4-aminodiphenylamine orsubstituted derivatives thereof is provided which comprises contactinganiline or substituted aniline derivatives and azobenzene or substitutedazobenzene derivatives or azoxy or hydrazo derivatives thereof in thepresence of a suitable solvent system, and reacting the aniline orsubstituted aniline derivatives and azobenzene or substituted azobenzenederivatives in the presence of a suitable base and a controlled amountof protic material at a suitable reaction temperature of about 10° C. toabout 150° C. in a confined reaction zone wherein the molar ratio ofprotic material to base is 0:1 to about 5:1, and further reacting withaniline or substituted aniline derivative in the presence of a suitablesolvent system, a suitable base and a controlled amount of proticmaterial at a reaction temperature of about 70° C. to about 200° C. in aconfined reaction zone, wherein the molar ratio of protic material tobase is 0:1 to about 5:1.

Further according to the invention, a process for preparing substitutedaromatic amines is provided which comprises contacting a nucleophiliccompound selected from the group consisting of aniline, substitutedaniline derivatives, aliphatic amines, substituted aliphatic aminederivatives and amides with a substituted aromatic azo compound in thepresence of a suitable solvent system, and reacting the nucleophiliccompound and the substituted aromatic azo compound or azoxy or hydrazoderivatives thereof in the presence of a suitable base and a controlledamount of protic material at a reaction temperature of about 70° C. toabout 200° C., wherein the molar ratio of protic material to base is 0:1to about 5:1, wherein the substituted aromatic azo compound is selectedfrom the group consisting of compounds represented by the formula##STR1## compounds represented by the formula ##STR2## compoundsrepresented by the formula ##STR3## and mixtures thereof, whereinR--NH--represents a substituent derived from a compound selected fromthe group consisting of aniline, substituted aniline derivatives,aliphatic amines, substituted aliphatic amine derivative and amides, R₁is an aromatic group, R₂ is selected from the group consisting ofaliphatic and aromatic groups, and X and Y are independently selectedfrom the group consisting of hydrogen, halides,--NO₂, --NH₂, arylgroups, alkyl groups, alkoxy groups, sulfonate groups, --SO₃ H, --OH,--COH, --COOH, and alkyl, aryl, arylalkyl or alkylaryl groups containingat least one --NH₂ group, wherein halides are selected from the groupconsisting of chlorine, bromine and fluorine and R₂ is an aromatic groupin substituted aromatic azo compounds (II) and (III). The substitutedaromatic azo compounds of (I), (II), and (III) also includes azoxy orhydrazo derivatives thereof.

Further according to the invention, a process for preparing alkylatedp-phenylenediamines or substituted derivatives thereof is provided whichcomprises reductively alkylating the substituted aromatic aminesprepared according to the invention.

Further according to the invention, a process for preparing substitutedaromatic amines is provided which comprises reacting the substitutedaromatic amine, prepared by reacting amide and an azo containingcompound to produce a substituted aromatic azo compound followed byreacting the substituted aromatic azo compound with a nucleophiliccompound, with ammonia under conditions which produce the correspondingsubstituted aromatic amine and an amide.

DETAILED DESCRIPTION OF THE INVENTION

This invention relates to a process for preparing substituted aromaticazo compounds comprising:

(a) contacting a nucleophilic compound selected from the groupconsisting of aniline, substituted aniline derivatives, aliphaticamines, substituted aliphatic amine derivatives and amides and an azocontaining compound represented by the formula X--R₁ --N═N--R₂ --Y orazoxy or hydrazo derivatives thereof in the presence of a suitablesolvent system, and

(b) reacting a nucleophilic compound selected from the group consistingof aniline, substituted aniline derivatives, aliphatic amines,substituted aliphatic amine derivatives and amides and an azo containingcompound represented by the formula X--R₁ --N═N--R₂ --Y or azoxy orhydrazo derivatives thereof in the presence of a suitable base and acontrolled amount of protic material at a reaction temperature of about10° C. to about 150° C. in a confined reaction zone, wherein the molarratio of protic material to base is 0:1 to about 5:1, wherein R₁ is anaromatic group, R₂ is selected from the group consisting of aliphaticand aromatic groups, and X and Y are independently selected from thegroup consisting of hydrogen, halides, --NO₂, --NH₂, aryl groups, alkylgroups, alkoxy groups, sulfonate groups, --SO₃ H, --OH, --COH, --COOH,and alkyl, aryl, arylalkyl or alkylaryl groups containing at least one--NH₂ group, wherein if R₂ is aliphatic, X is in the meta or orthoposition on R₁, and if R₂ is aromatic, at least one of X and Y is in themeta or ortho position on R₁ and R₂, respectively, and wherein halidesare selected from the group consisting of chloride, bromide andfluoride.

For producing substituted aromatic amines, the process of the inventionfurther comprises:

(c) reacting the substituted aromatic azo compound with a nucleophiliccompound independently selected from the group consisting of aniline,substituted aniline derivatives, aliphatic amines, substituted aliphaticamine derivatives and amides in the presence of a suitable solventsystem, a suitable base and a controlled amount of protic material at areaction temperature of about 70° C. to about 200° C. in a confinedreaction zone, wherein the molar ratio of protic material to base is 0:1to about 5:1. Independently selected nucleophilic compound is usedherein to mean that the nucleophilic compound can be the same ordifferent from the nucleophilic compound used in the reaction of thenucleophilic compound with the azo containing compound.

For producing alkylated p-phenylenediamines or substituted derivativesthereof, the process of the invention further comprises:

(d) reductively alkylating the substituted aromatic amines.

For producing substituted aromatic amines when the nucleophilic compoundis an amide, the process of the invention further comprises:

(c') reacting the substituted aromatic amine with ammonia underconditions which produce the corresponding substituted aromatic amineand amide.

In one embodiment, this invention relates to a process for preparing4-ADPA or substituted derivatives thereof comprising:

(a) contacting aniline or substituted aniline derivatives and azobenzeneor substituted azobenzene derivatives or azoxy or hydrazo derivativesthereof in the presence of a suitable solvent system, and

(b) reacting the aniline or substituted aniline derivatives andazobenzene or substituted azobenzene derivatives or azoxy or hydrazoderivatives thereof in the presence of a suitable base and a controlledamount of protic material at a reaction temperature of about 10° C. toabout 150° C. in a confined reaction zone wherein the molar ratio ofprotic material to base is 0:1 to about 5:1, and

(c) reacting the product of (b) with aniline or substituted anilinederivatives in the presence of a suitable solvent system, a suitablebase and a controlled amount of protic material at a reactiontemperature of about 70° C. to about 200° C. in a confined reactionzone, wherein the molar ratio of protic material to base is 0:1 to about5:1.

For producing alkylated p-phenylenediamines or substituted derivativethereof, the process of the invention further comprises:

(d) reductively alkylating the 4-ADPA or substituted derivativesthereof.

This invention further relates to a process for preparing substitutedaromatic amines comprising:

(a) contacting a nucleophilic compound selected from the groupconsisting of aniline, substituted aniline derivatives, aliphaticamines, substituted aliphatic amine derivatives and amides and asubstituted aromatic azo compound or azoxy or hydrazo derivativesthereof in the presence of a suitable solvent system, and

(b) reacting the nucleophilic compound and the substituted aromatic azocompound or azoxy or hydrazo derivatives thereof in the presence of asuitable base and a controlled amount of protic material at a reactiontemperature of about 70° C. to about 200° C. wherein the molar ratio ofprotic material to base is 0:1 to about 5:1, wherein the substitutedaromatic azo compound is selected from the group consisting of compoundsrepresented by the formula ##STR4## compounds represented by the formula##STR5## compounds represented by the formula ##STR6## and mixturesthereof, wherein R--NH-- represents a substituent derived from acompound selected from the group consisting of aniline, substitutedaniline derivatives, aliphatic amines, substituted aliphatic aminederivatives and amides, R₁ is an aromatic group, R₂ is selected from thegroup consisting of aliphatic and aromatic groups, and X and Y areindependently selected from the group consisting of hydrogen, halides,--NO₂, --NH₂, aryl groups, alkyl groups, alkoxy groups, sulfonategroups, --SO₃ H, --OH, --COH, --COOH, and alkyl, aryl, arylalkyl oralkylaryl groups containing at least one --NH₂ group, wherein halidesare selected from the group consisting of chlorine, bromine and fluorineand R₂ is an aromatic group in substituted aromatic azo compounds (II)and (III).

For producing alkylated p-phenylenediamines or substituted derivativesthereof, the process of the invention further comprises:

(c) reductively alkylating the substituted aromatic amines.

For producing substituted aromatic amines when the nucleophilic compoundis an amide, the process of the invention further comprises:

(c') reacting the substituted aromatic amine with ammonia underconditions which produce the corresponding substituted aromatic amineand amide.

In one embodiment, the substituted aromatic azo compound is prepared byreacting. 4-nitrosodiphenylamine with an aromatic primary amine or analiphatic primary amine.

In the preparation of substituted aromatic azo compounds, the molarratio of a nucleophilic compound selected from the group consisting ofaniline, substituted aniline derivatives, aliphatic amines, substitutedaliphatic amine derivatives and amides to X--R₁ --N═N--R₂ --Y or azoxyor hydrazo derivatives thereof can vary from a large excess of X--R₁--N═N--R₂ --Y or azoxy or hydrazo derivatives thereof to a large excessof a nucleophilic compound selected from the group consisting ofaniline, substituted aniline derivatives, aliphatic amines, substitutedaliphatic amine derivatives and amides. Preferably, the reaction isconducted utilizing an excess of a nucleophilic compound selected fromthe group consisting of aniline, substituted aniline derivatives,aliphatic amines, substituted aliphatic amine derivatives and amides.More preferably, the molar ratio of nucleophilic compound to X--R₁--N═N--R₂ --Y or azoxy or hydrazo derivatives thereof is at least about1:1.

In the preparation of substituted aromatic amines by the reaction of anucleophilic compound with a substituted aromatic azo compound, themolar ratio of a nucleophilic compound selected from the groupconsisting of aniline, substituted aniline derivatives, aliphaticamines, substituted aliphatic amine derivatives and amides tosubstituted aromatic azo compounds can vary from a large excess ofsubstituted aromatic azo compound to a large excess of a nucleophiliccompound selected from the group consisting of aniline, substitutedaniline derivatives, aliphatic amines, substituted aliphatic aminederivatives and amides. Preferably, the reaction is conducted utilizingan excess of a nucleophilic compound as defined above. More preferably,the molar ratio of nucleophilic compound to substituted aromatic azocompound is at least about 1:1.

As used herein, the term "substituted aniline derivatives" means anilinecontaining one or more electron withdrawing or electron releasingsubstituents on the aromatic ring. Applicable substituents include, butare not limited to, halides, --NO₂, --NH₂, alkyl groups, alkoxy groups,sulfonate groups, --SO₃ H, --OH, --COOH and aryl, arylalkyl or alkylarylgroups containing at least 1 --NH₂ group. Halides are selected from thegroup consisting of chloride, bromide or fluoride. The preferred alkyland alkoxy groups contain from 1 to about 6 carbon atoms. The preferredaryl, arylalkyl and alkylaryl groups contain from about 6 to about 18carbon atoms. Examples of substituted aniline derivatives include, butare not limited to, 2-methoxyaniline, 4-methoxyaniline, 4-chloroaniline,p-toluidine, 4-nitroaniline, 3-bromoaniline, 3-bromo-4-aminotoluene,p-aminobenzoic acid, 2,4-diaminotoluene, 2,5-dichloroaniline,1,4-phenylenediamine, 4,4'-methylenedianiline, 1,3,5-triaminobenzene andmixtures thereof.

Aniline or substituted aniline derivatives can be added directly or canbe formed in situ by addition of a compound that will form aniline orthe corresponding aniline derivative under the conditions present in thereaction system.

Amides that can, be employed according to the invention include aromaticamides, aliphatic amides, substituted aromatic amide derivatives,substituted aliphatic amide derivatives and diamides having the formula:##STR7## wherein R₄ and R₅ are independently selected from the groupconsisting of aromatic groups, aliphatic groups and a direct bond, and Ais selected from the group consisting of ##STR8## --SO₂ --, --O--, --S--and a direct bond.

The aliphatic amides and substituted aliphatic amide derivatives thatcan be employed according to the invention are represented by theformula: ##STR9## wherein n is 0 or 1, R₃ is selected from the groupconsisting of alkyl, arylalkyl, alkenyl, arylalkenyl, cycloalkyl andcycloalkenyl groups and X is selected from the group consisting ofhydrogen, --NO₂, --NH₂, aryl groups, alkoxy groups, sulfonate groups,--SO₃ H, --OH, --COH, --COOH, and alkyl, aryl, arylalkyl or alkyl arylgroups containing at least one --NH₂ group. The preferred alkyl andalkoxy groups contain from 1 to about 6 carbon atoms. The preferredaryl, arylalkyl and alkyl aryl groups contain from about 6 to about 18carbon atoms.

Examples of aliphatic amides and substituted aliphatic amide derivativesinclude, but are not limited to, isobutyramide, urea, acetamide,propylamide and mixtures thereof.

As used herein, the term "substituted aromatic amide derivatives" meansaromatic amides containing one or more electron withdrawing or electronreleasing substituents on the aromatic ring. Applicable substituentsinclude, but are not limited to, halides, --NO₂, --NH₂, alkyl groups,alkoxy groups, sulfonate groups, --SO₃ H, --OH, --COH, --COOH, andalkyl, aryl, arylalkyl or alkyl- aryl groups containing at least one--NH₂ group. Halides are selected from the group consisting of chloride,bromide and fluoride. The preferred alkyl and alkoxy groups contain from1 to about 6 carbon atoms. The preferred aryl, arylalkyl and alkyl arylgroups contain from about 6 to about 18 carbon atoms.

Examples of aromatic amides and substituted aromatic amide derivativesinclude, but are not limited to, benzamide, 4-methylbenzamide,4-methoxybenzamide, 4-chlorobenzamide, 2-methylbenzamide,4-nitrobenzamide, 4-aminobenzamide and mixtures thereof.

Diamides that can be employed according to the process of the inventioninclude, but are not limited to, adipamide, oxalic amide, terephthalicdiamide, 4,4'-biphenyldicarboxamide and mixtures thereof.

Aliphatic amines and substituted aliphatic amines that can be employedaccording to the invention are compounds selected from the groupconsisting of compounds represented by the formula X'--R₆ --NH--R₇ --Y'and compounds represented by the formula: ##STR10## wherein R₆ isselected from the group consisting of alkyl, alkenyl, cycloalkyl andcycloalkenyl groups, R₇ is selected from the group consisting of adirect bond, alkyl, alkenyl, cycloalkyl and cycloalkenyl groups, R₈ andR₈ are independently selected from the group consisting of alkyl andalkenyl groups, Z is selected from the group consisting of a directbond, --NH--, --N(R₁₀)--, --O--and --S--, wherein R₁₀ is an alkyl group,and X' and Y' are independently selected from the group consisting ofhydrogen, halides, --NO₂, --NH₂, aryl groups, alkoxy groups, sulfonategroups, --SO₃ H, --OH, --COH, --COOH, and alkyl, aryl, arylalkyl oralkylaryl groups containing at least one --NH₂ group. Halides areselected from the group consisting of chloride, bromide and fluoride.The preferred aliphatic groups of R₆ and R₇ contain from 1 to about 12carbon atoms. The preferred aryl, arylalkyl and alkylaryl groups containfrom about 6 to about 18 carbon atoms. The preferred alkoxy groupscontain from 1 to about 6 carbon atoms.

Examples of aliphatic amines and substituted aliphatic amine derivativesinclude, but are not limited to, cyclohexylamine, 2-butylamine,isopropylamine, 2-hexylamine, 2-heptylamine, 1,4-dimethylpentylamine,1-methylheptylamine, 1-ethyl-3-methylpentylamine,1,3-dimethylbutylamine, octylamine, piperidine, piperazine,hexamethylene diamine, 2-amino-1-propanol, 2-amino-1-butanol,6-aminohexanoic acid and mixtures thereof.

As used herein, the term "azo containing compounds" are compounds of theinvention that are represented by the formula X--R₁ --N═N--R₂ --Y orazoxy or hydrazo derivatives thereof wherein R₁ is an aromatic group, R₂is selected from the group consisting of aliphatic and aromatic groupsand X and Y are independently selected from the group consisting ofhydrogen, halides, --NO₂, --NH₂, aryl groups, alkyl groups, alkoxygroups, sulfonate groups, --SO₃ H, --OH, --COH, --COOH, and alkyl, aryl,arylalkyl or alkylaryl groups containing at least one --NH₂ group. WhenR₂ is an aliphatic group, X is in the meta or ortho position on R₁. WhenR₂ is aromatic, at least one of X and Y is in the meta or ortho positionon R₁ and R₂, respectively. Halides are selected from the groupconsisting of chloride, bromide and fluoride. The preferred aliphaticgroups of R₁ and R₂ contain from 1 to about 12 carbon atoms and thepreferred aromatic groups of R₁ and R₂ contain from about 6 to about 18carbon atoms. The preferred alkyl and alkoxy groups contain from 1 toabout 6 carbon atoms. The preferred aryl, arylalkyl and alkylaryl groupscontain from about 6 to about 18 carbon atoms. Examples of azocontaining compounds include, but are not limited to, azobenzene,substituted azobenzene derivative, azoxybenzene,4-(phenylazo)diphenylamine, 1,2-diphenylhydrazine, and mixtures thereof.

When the azo containing compound is azobenzene, azobenzene can beproduced via the oxidative coupling of aniline in the presence of asuitable base. When the nucleophilic compound used to react withazobenzene is aniline and the reaction is conducted under aerobicconditions, the azobenzene can be produced in-situ via the oxidativecoupling of aniline in the presence of a suitable base. The oxidativecoupling of aniline is known in the art, see Jeon, S. and Sawyer, D. T.,"Hydroxide-Induced Synthesis of the Superoxide Ion from Dioxygen andAniline, Hydroxylamine, or Hydrazine", Inorg. Chem., Vol. 29, pp.4612-15 (1990), and the reaction conditions defined herein for theproduction of the substituted aromatic azo compounds are sufficient forthe oxidative coupling of aniline to azobenzene.

As used herein, the term "substituted azobenzene derivatives" meansazobenzene containing one or more electron withdrawing or electronreleasing substituents on one or both of the aromatic rings. Applicablesubstituents include, but are not limited to, halides, --NO₂, --NH₂,alkyl groups, alkoxy groups, sulfonate groups, --SO₃ H, --OH, --COOH andaryl, arylalkyl or alkylaryl groups containing at least one --NH₂ group.Halides are selected from the group consisting of chloride, bromide andfluoride. The preferred alkyl and alkoxy groups contain from 1 to about6 carbon atoms. The preferred aryl, arylalkyl, and alkylaryl groupscontain from about 6 to about 18 carbon atoms. Examples of substitutedazobenzene derivatives include, but are not limited to,3,4'-dichloroazobenzene, p-phenylazobenzene sulfonic acid,p-(2,4-dihydroxyphenylazo)benzene sulfonic acid, and mixtures thereof.

Suitable solvent systems include, but are not limited to, solvents suchas dimethylsulfoxide, nucleophilic compounds such as substituted anilinederivatives, aniline and amides having a melting point below thereaction temperature, e.g., molten benzamide, dimethylformamide,N--methyl-2-pyrrolidone, pyridine, ethyleneglycoldimethyl ether, aminessuch as diisopropylethylamine, sec-butyl amine and 2-heptylamine, andthe like, and mixtures thereof. As described in more detail below,solvent mixtures can be utilized wherein in one or more of the suitablesolvents and another solvent, such as a controlled amount of a proticsolvent, e.g., methanol or water, are combined.

Suitable bases include, but are not limited to, organic and inorganicbases such as alkali metals, such as sodium metal, alkali metalhydrides, hydroxides and alkoxides, such as sodium hydride, lithiumhydroxide, sodium hydroxide, cesium hydroxide, potassium hydroxide,potassium t-butoxide, and the like, including mixtures thereof. Otheracceptable base materials include, but are not limited to, phasetransfer catalysts in conjunction with a suitable base source such astetrasubstituted ammonium hydroxides or halides wherein each substituentis independently selected from alkyl, aryl or aryl groups wherein thealkyl, aryl and arylalkyl groups preferably have 1 to about 18 carbonatoms, including tetraalkyl ammonium hydroxides, e.g.,tetramethylammonium hydroxide, tetraalkylammonium halides, e.g.,tetrabutylammonium chloride, aryl, trialkylammonium hydroxides, e.g.,phenyltrimethylammonium hydroxide, arylalkyl, trialkyl ammoniumhydroxides, e.g., benzyltrimethylammonium hydroxide, alkyl substituteddiammonium hydroxides, e.g., bis-dibutylethylhexamethylenediammoniumhydroxide, and other combinations of phase transfer catalysts andsuitable bases such as suitable bases in conjunction with aryl ammoniumsalts, crown ethers and the like, amine bases such as lithium,bis(trimethylsilyl) amide, 2-aminoheptane, and the like, and alkylmagnesium halides, including mixtures thereof. Preferred materials foruse as bases are alkali metal hydroxides, such as potassium hydroxide,alkali metal alkoxides such as potassium t-butoxide, alkali metalhydroxides or alkoxides in conjunction with a phase transfer catalystsuch as potassium hydroxide in conjunction with crown ethers, andtetraalkylammonium hydroxides such as tetramethylammonium hydroxide ortetrabutylammonium hydroxide.

Preferably, the base is added to the nucleophilic compound to produce amixture which is then combined with the azo containing compound orsubstituted aromatic azo compound. Alternatively, the base can be addedafter the nucleophilic compound and azo containing compound orsubstituted aromatic azo compound have been combined. Addition ofmaterials can be above or below surface addition.

For the preparation of substituted aromatic azo compounds, the amount ofbase employed according to the invention can be conveniently expressedin terms of a molar ratio of suitable base to azo containing compound.Broadly, the molar ratio of base to azo containing compound will beabout 1:1 to about 10:1, preferably about 1:1 to about 4:1, and mostpreferably about 1:1 to about 2:1.

For the preparation of substituted aromatic amines, the amount of baseemployed according to the invention can be conveniently expressed interms of a molar ratio of suitable base to substituted aromatic azocompound. Broadly, the molar ratio of base to substituted aromatic azocompound will be about 1:1 to about 10:1, preferably about 1:1 to about4:1, and most preferably, about 1:1 to about 2:1.

The reaction of the nucleophilic compound with the azo containingcompound is conducted at a temperature within the range of from about10° C. to about 150° C., such as from about 20° C. to about 120° C.,preferably from about 30° C. to about 100° C. A most preferredtemperature for conducting the reaction of the nucleophilic compoundwith the azo containing compound is from about 50° C. to about 90° C.

The reaction of the nucleophilic compound with the substituted aromaticazo compound is conducted at a temperature within the range of fromabout 70° C. to about 200° C., such as from about 70° C. to about 190°C., preferably from about 70° C. to about 180° C. A most preferredtemperature for conducting the reaction of the nucleophilic compoundwith the substituted aromatic azo compound is from about 130° C. toabout 170° C.

Control of the amount of protic material present in the reaction of thenucleophilic compound with the azo containing compound is important. Theamount of protic material employed according to the invention can beconveniently expressed in terms of a molar ratio based on the amount ofbase present at the beginning of the reaction of nucleophilic compoundand azo containing compound. Broadly, the molar ratio of protic materialto base will be from 0:1 to about 5:1, preferably from 0:1 to about 3:1,and most preferably 0:1 to about 1:1. Thus, the present reaction couldbe conducted under anhydrous conditions. As used herein for the reactionof nucleophilic compound and azo containing compound, the term"controlled amount" of protic material is an amount up to that whichinhibits the reaction of nucleophilic compound with azo containingcompound. The upper limit for the amount of protic material present inthe reaction varies with the solvent. In addition, the amount of proticmaterial tolerated will vary with the type of base, amount of base, andbase cation, used in the various solvent systems. However, it is withinthe skill of one in the art, utilizing the teachings of the presentinvention, to determine the specific upper limit of the amount of proticmaterial for a specific solvent, type and amount of base, base cationand the like. The minimum amount of protic material necessary tomaintain selectivity of the desired products will also depend upon thesolvent, type and amount of base, base cation and the like, that isutilized and can also be determined by one skilled in the art.

Control of the amount of protic material present in the reaction of thenucleophilic compound with the substituted aromatic azo compound isimportant. The amount of protic material employed according to theinvention can be conveniently expressed in terms of a molar ratio basedon the amount of base present at the beginning of the reaction ofnucleophilic compound and substituted aromatic azo compound. Broadly,the molar ratio of protic material to base will be from 0:1 to about5:1, preferably from 0:1 to about 1:1. Thus, the present reaction couldbe conducted under anhydrous conditions. As used herein for the reactionof nucleophilic compound and substituted aromatic azo compound, the term"controlled amount" of protic material is an amount up to that whichinhibits the reaction of nucleophilic compound with substituted aromaticazo compound. The upper limit for the amount of protic material presentin the reaction varies with the solvent. In addition, the amount ofprotic material tolerated will vary with the type of base, amount ofbase, and base cation, used in the various solvent systems. However, itis within the skill of one in the art, utilizing the teachings of thepresent invention, to determine the specific upper limit of the amountof protic material for a specific solvent, type and amount of base, basecation and the like. The minimum amount of protic material necessary tomaintain selectivity of the desired products will also depend upon thesolvents, type and amount of base, base cation and the like, that isutilized and can also be determined by one skilled in the art.

Since the amount of protic material present in the reaction isimportant, it is possible to reduce the amount of protic materialpresent as much as possible and then add back to the reaction thedesired amount. Protic materials that can be utilized to add back to thereaction are known to those skilled in the art and include, but are notlimited to, water, methanol, isoamyl alcohol, t-butanol and the like,and mixtures thereof. Methods for measuring the amount of proticmaterial and for reducing the amount of protic material as much aspossible are well known in the art. For example, the amount of waterpresent in certain reagents can be determined by utilizing aKarl-Fischer apparatus, and the amount of water can be reduced throughdistillation and/or drying under reduced pressure, drying in thepresence of P₂ O₅ and other agents, azeotropic distillation utilizing,for example, xylene, and the like, including combinations thereof.

In one embodiment for controlling the amount of protic material duringthe reaction of nucleophilic compound with azo containing compound orsubstituted aromatic azo compound, a desiccant is added so as to bepresent during the reaction of nucleophilic compound with azo containingcompound or substituted aromatic azo compound. For example, when theprotic material is water, the desiccant removes water present during thereaction of nucleophilic compound and azo containing compound orsubstituted aromatic azo compound and results in higher conversion ofazo containing compound or substituted aromatic azo compound and yieldsof substituted aromatic azo compound or substituted aromatic amine. Asused herein, desiccant is a compound present during the reaction ofnucleophilic compound and azo containing compound or substitutedaromatic azo compound in addition to the suitable base used. Examples ofsuitable desiccants include, but are not limited to, anhydrous sodiumsulfate, molecular sieves, such as types 4A, 5A, and 13X available fromthe Union Carbide Corporation, calcium chloride, tetramethylammoniumhydroxide dihydrate, anhydrous bases such as KOH and NaOH, and activatedalumina.

In another embodiment for controlling the amount of protic materialduring the reaction of nucleophilic compound and azo containing compoundor substituted aromatic azo compound, protic material is continuouslyremoved from the reaction mixture by distillation. If the proticmaterial present forms an azeotrope with one of the compounds in thereaction mixture, the protic material can be removed by continuousazeotropic distillation of protic material utilizing the azeotrope. Thecontinuous removal of protic material allows the use of lower amounts ofbase in the reaction of nucleophilic compound and azo containingcompound or substituted aromatic azo compound while achieving very highconversion of azo containing compound or substituted aromatic azocompound and excellent yields of substituted aromatic azo compound orsubstituted aromatic amine.

Generally, the reactions can be conducted under aerobic or anaerobicconditions. When the nucleophilic compound is a secondary aliphaticamine, the reactions can be conducted only under aerobic conditions,i.e., under anaerobic conditions the only applicable aliphatic amines orsubstituted aliphatic amine derivatives are those having the formulaX'--R₆ --NH₂. Under aerobic conditions the reaction is conductedessentially as described above in the reaction zone which is exposed tooxygen, usually by exposure to air. Under aerobic conditions, thepressure at which the reaction is conducted can vary and the optimalpressure, as well as the optimal combination of pressure andtemperature, are easily determined by one skilled in the art. Forexample, the reaction can be conducted at a pressure ranging from about0 psig (0 kg/cm²) to about 250 psig (17.6 kg/cm²), such as from about 14psig (1 kg/cm²) to about 150 psig (10.5 kg/cm²). Under anaerobicconditions, the reactions can be conducted at atmospheric pressure orreduced or elevated pressures, in the presence of an inert gas such as,for example, nitrogen or argon. Optimal conditions for a particular setof reaction parameters, such as temperature, base, solvent and the like,are easily determined by one skilled in the art utilizing the teachingof the present invention.

Reductive alkylation of substituted aromatic amines, e.g., 4-ADPA, toproduce antioxidants or antiozonants can be conducted by any of severalwellknown methods. See, for example, U.S. Pat. No. 4,900,868.Preferably, substituted aromatic amines and a suitable ketone oraldehyde are reacted in the presence of hydrogen and platinum-on-carbonas catalysts. Suitable ketones include, but are not limited to,methylisobutylketone (MIBK), acetone, methylisoamylketone and2-octanone.

Aminolysis of substituted aromatic amines containing an aromatic amidebond, which can be prepared by reacting an amide as the nucleophiliccompound and an azo containing compound to produce a substitutedaromatic azo compound followed by reacting the substituted aromatic azocompound with a nucleophilic compound, can be conducted by reacting thesubstituted aromatic amine with ammonia to produce the correspondingsubstituted aromatic amine and an amide which can be recycled. See forexample, Jencks, W.P., J. Am. Chem. Soc., Vol. 92, pp. 3201-3202 (1970).Preferably, the substituted aromatic amine containing an aromatic amidebond is reacted with ammonia in the presence of a solvent, e.g.,methanol.

Contemplated equivalents of the reactants and reagents set forth aboveare reactants and reagents otherwise corresponding thereto and havingthe same general properties wherein one or more of the various groups,e.g., --NO₂, are simple variations. In addition, where a substituent isdesignated as, or can be, a hydrogen, the exact chemical nature of asubstituent which is other than hydrogen at that position is notcritical so long as it does not adversely affect the overall activityand/or synthesis procedure.

The chemical reactions described above are generally disclosed in termsof their broadest application to the process of this invention.Occasionally, the reaction conditions may not be applicable asspecifically described to each reactant and reagent within the disclosedscope. For example, certain suitable bases may not be as soluble in onesolvent as they are in other solvents. The reactants and reagents forwhich this occurs will be readily recognized by those skilled in theart. In all such cases, either the reactions can be successfullyperformed by conventional modifications known to those skilled in theart, e.g., by appropriate adjustments in temperature, pressure and thelike, by changing to alternative conventional reagents such as othersolvents or other bases, by routine modification of reaction conditions,and the like, or other reactions disclosed herein or otherwiseconventional, will be applicable to the process of this invention. Inall preparative methods, all starting materials are known or are readilypreparable from known starting materials.

EXAMPLES

Materials and Methods: Aniline, aniline derivatives and azobenzene werepurchased from Aldrich Chemical, were reagent grade and were usedwithout further purification. Solvents were purchased from AldrichChemical and were anhydrous grade. The tetramethylammonium hydroxide waspurchased as the pentahydrate.

HPLO Assay

Reverse phase HPLC was used to analyze the reaction mixtures. A 5 μmBeckman/Altex Ultrasphere-ODS (4.6×150 mm) column was employed using abinary gradient pump system. Absorption in the UV was monitored at 254nm.

A Waters 600 series HPLC equipped with a Vydac 201HS54 (4.6×250 mm)column and UV detection at 254 nm was used to monitor all reactions. Theexternal standard method was utilized in all the analysis. Authenticsamples of products to be used as standards were prepared by knownliterature methods.

    ______________________________________                                        Elution Gradient                                                                                      % Solvent B                                           Time (min.)                                                                            % Solvent A (Water)                                                                          (40% Methanol in ACN)                                 ______________________________________                                        0        75             25                                                    35       20             80                                                    40       0              100                                                   45       0              100                                                   46       75             25                                                    55       75             25                                                    ______________________________________                                    

Example 1

This example illustrates the production of 4-ADPA from the reaction ofaniline and azobenzene and base using a phase transfer catalyst.

A) A solution of 1.8 g of azobenzene, 2.6 g of 18-crown-6, 1 g of KOHand 5 g of aniline was stirred at 70° C. under nitrogen for 72 hours. Analiquot was taken out for HPLC analysis. The yield of 4-ADPA based onazobenzene was 58%.

B) A solution of 1.8 g of azobenzene, 1.5 g of potassium methoxide, 2.6g of 18-crown-6 and 5 g of aniline was stirred at 100° C. under nitrogenfor 3 hours. An aliquot was taken out for HPLC analysis. The yield of4-ADPA based azobenzene was 32%.

C) A solution of 1.8 g of azobenzene, 2.6 g of 18-crown-6, 2.24 g ofpotassium t-butoxide and 5 g of aniline was stirred at 80° C. undernitrogen for 2 hours. An aliquot was taken out for HPLC analysis. Theyield of 4-ADPA based on azobenzene was 100%.

Example 2

This example illustrate the production of 4-ADPA from the reaction ofaniline and azobenzene in the presence of a base.

A) A solution of 1.8 g of azobenzene, 1 g of KOH and 5 g of aniline wasstirred at 120° C. under nitrogen for 12 hours. An aliquot was taken outfor HPLC analysis. The yield of 4-ADPA based on azobenzene was 19%.

B) A solution of 1.8 g of azobenzene, 2 g of KOH and 5 g of aniline wasstirred at 150° C. under nitrogen for 12 hours. An aliquot was taken outfor HPLC analysis. The yield of 4-ADPA based on azobenzene was 38 %.

C) A solution of 1.8 g of azobenzene, 0.5 g of NaH and 5 g of anilinewas stirred at 80° C. under nitrogen for 12 hours. An aliquot was takenout for HPLC analysis. The yield of 4-ADPA based on azobenzene was 97%.

Example 3

This example illustrates the effect of protic material on the productionof 4-(phenylazo)diphenylamine from the reaction of aniline andazobenzene in the presence of a base and phase transfer catalyst.

A mixture of aniline (1.25 g), azobenzene (0.45 g), potassium t-butoxide(0.55 g), and 18-crown-6 (0.65 g) was stirred under nitrogen. Variableamounts of water was added to the reaction and the solution was heatedto 80° C. for two hours after which time an aliquot was removed andanalyzed by HPLC.

                  TABLE 1                                                         ______________________________________                                        Mole Ratio    % Yield                                                         Water: t-Butoxide                                                                           4-(Phenylazo)-diphenylamine                                     ______________________________________                                        10            0                                                               3             1                                                               1             7                                                               0.5           50                                                              ______________________________________                                    

Example 4

This example illustrates the production of 4-ADPA from the reaction ofaniline, azobenzene, base and phase transfer catalyst in the presence ofvarious solvents.

A) A solution of 1.8 g of azobenzene, 2.24 g of potassium hydroxide, 2.6g of 18-crown-6 and 0.9 g of aniline was stirred in 5 g of DMSO at 120°C. under nitrogen for 72 hours. An aliquot was taken out for HPLCanalysis. The yield of 4-ADPA based on azobenzene was 10%.

B) A solution of 1.8 g of azobenzene, 2.2 g of potassium t-butoxide, 2.6g of 18-crown-6 and 0.9 g of aniline was stirred in 5 g of ethyleneglycol at 140° C. under nitrogen for 12 hours. An aliquot was taken outfor HPLC analysis and . The HPLC yield of 4-ADPA based on azobenzene was30%.

C) A solution of 1.8 g of azobenzene, 2.2 g of potassium t-butoxide, 2.6g of 18-crown-6 and 0.9 g of aniline was stirred in 3 g ofN-methyl-2-pyrrolidone at 140° C. under nitrogen for 12 hours. Analiquot was removed for HPLC analysis. The yield of 4-ADPA based onazobenzene was 5%.

Example 5

This example illustrates the reaction of substituted aniline derivativeswith azobenzene to produce the corresponding substituted 4-ADPAderivative.

A) A solution of 1.8 g of azobenzene, 2.2 g of potassium t-butoxide and5.35 g of p-toluidine was stirred at 150° C. under nitrogen for 12hours. An aliquot was taken out for HPLC analysis. The yield of 4-ADPAderivative based on azobenzene was 71%.

B) A solution of 1.8 g of azobenzene, 2.2 g of potassium t-butoxide and5 g of p-anisidine was stirred at 140° C. under nitrogen for 12 hours.An aliquot was taken out for HPLC analysis. The yield of 4-ADPAderivative based on azobenzene was 35%.

C) A solution of 1.8 g of azobenzene, 2.2 g of potassium t-butoxide, 2.6g of 18-crown-6 and 5 g of p-chloroaniline was stirred at 135° C. undernitrogen for 4 hours. An aliquot was taken out for HPLC analysis. Theyield of 4-ADPA derivative based on azobenzene was 49%.

Example 6

This example illustrates the production of 4-ADPA from the reaction ofazoxybenzene, aniline, base and phase transfer catalyst.

A solution of 12 g of azoxybenzene, 1 g of potassium hydroxide, 2.6 g of18-crown-6 and 5 g of aniline was stirred at 150° C. under nitrogen for4 hours. An aliquot was taken out for HPLC analysis. The yield of 4-ADPAbased on azoxybenzene was 91%.

Example 7

This example illustrates the effect of water on the production of 4-ADPAfrom the reaction of 4-(phenylazo)-diphenylamine with a nucleophile.

A solution of 0.3 g of 4-(phenylazo)diphenylamine, 0.5 g of aniline,0.25 g of potassium t-butoxide, 0.3 g of 18-crown-6 and various amountsof water was heated under nitrogen for 4 hours. An aliquot was removedfor HPLC analysis. The results are summarized in Table 2.

                  TABLE 2                                                         ______________________________________                                        Mole Ratio       % Yield                                                      Water: t-Butoxide                                                                              4-ADPA                                                       ______________________________________                                        10               0                                                            5                6                                                            3                2                                                            1                100                                                          0.5              100                                                          Anhydrous        36                                                           ______________________________________                                    

Example 8

This example illustrate the production of 4-ADPA from the reaction of2-heptylamine, 4-(phenylazo)diphenylamine, base and phase transfercatalyst.

A solution of 1.35 g of 4-(phenylazo)diphenylamine, 3 g of2-aminoheptane, 1.12 g of potassium t-butoxide and 1.3 g of 18-crown-6was heated under nitrogen for 3 hours. An aliquot was taken out for HPLCanalysis. The yield of 4-ADPA based on 4-(phenylazo)diphenylamine was23%.

Example 9

This example illustrates the production of 4-ADPA from the reaction of4-(phenylazo)diphenylamine and 2-aminoheptane.

A solution of 1.32 g of 4-(phenylazo)diphenylamine and 3.1 g of2-aminoheptane was heated under nitrogen for 3 hours. An aliquot wasremoved for HPLC analysis. The yield of 4-ADPA based on4-(phenylazo)diphenylamine was 30%.

Example 10

This example illustrates the production of 4-ADPA from the reaction of4-(phenylazo)diphenylamine and a substituted aromatic amine.

A solution of 2.73 g of 4-(phenylazo)diphenylamine, 5 g of1,4-phenylenediamine, 2.24 g of potassium t-butoxide and 2.6 g of18-crown-6 was heated under nitrogen for 30 minutes. An aliquot wasremoved for HPLC analysis. The yield of 4-ADPA based on4-(phenylazo)diphenylamine was 59%.

Example 11

This example illustrates the production 4,4'-diaminodiphenylamine, a4-ADPA derivative, produced from the reaction of a substituted aromaticamine, 1,4-phenylenediamine, with azobenzene.

A solution of 1.8 g of azobenzene 5 g of 1,4-phenylenediamine, 2.24 g ofpotassium t-butoxide and 2.6 g of 18-crown-6 was heated under nitrogenfor 30 minutes. An aliquot was removed for HPLC analysis. The yield of4,4'-diaminodiphenylamine based on azobenzene was 30%.

Example 12

This example illustrates the production of a substituted aromatic azocompound from the reaction of azobenzene and a substituted aromaticamine.

A solution of 1.8 g of azobenzene, 2.2 g of potassium t-butoxide, 2.6 gof 18-crown-6 and 5 g of substituted aniline was stirred at 80° C. for 1hour. An aliquot was taken out for HPLC analysis. Yields of substitutedazo compounds are based on azobenzene.

                  TABLE 3                                                         ______________________________________                                                           % Yield                                                    Substituted Aromatic Amine                                                                       Substituted Azo Compound                                   ______________________________________                                        p-chloroaniline    19%                                                        p-methylaniline    18%                                                        p-methoxyaniline   28%                                                        ______________________________________                                    

Example 13

This example illustrates the production of a substituted azo compoundfrom the reaction of azobenzene and aniline.

A solution of 1.8 g of azobenzene, 1 g of potassium hydroxide, 2.6 g of18-crown-6 and 5 g of aniline was stirred at 80° C. for 2 hour. Analiquot was taken out for HPLC analysis. The yield of4-(phenylazo)diphenylamine based on azobenzene was 14%.

Example 14

This example illustrates the production of a substituted aromatic aminefrom the reaction of an aromatic amide with azobenzene.

A mixture of 1.8 g of azobenzene, 2.6 g of 18-crown-6, 2.6 g ofpotassium t-butoxide was dissolved in 5 g of molten benzamide. Thereaction was stirred at 135° C. for 12 hour under nitrogen. An aliquotwas taken out for HPLC analysis. The yield of 4-aminobenzanilide basedon azobenzene was 17%.

Example 15

This example illustrates the production of 4-ADPA from the reaction of1,2-diphenylhydrazine and an aromatic amine nucleophile.

A mixture of 1.8 g of 1,2-diphenylhydrazine, 2.2 g of potassiumt-butoxide, 2.6 g of 18-crown-6 and 5 g of aniline was stirred at 135°C. for 12 hour. An aliquot was taken out for HPLC analysis. The yield of4-ADPA based on 1,2-diphenylhydrazine was 9%.

Example 16

This example illustrates the production of 4-(phenylazo) diphenylamineand substituted derivatives thereof from the reaction of aniline orsubstituted aniline derivatives and azobenzene.

(a) 10 mmole of azobenzene, 20 mmole of potassium t-butoxide and 10mmole of 18-crown-6 was stirred in 10 g of aniline under nitrogen at 80°C. for 30 minutes. A weighted aliquot was sampled for HPLC and was foundto contain 40% of 4-(phenylazo)diphenylamine, 50% of azobenzene and 10%of hydrazobenzene.

(b) 10 mmole of azobenzene, 20 mmole of potassium t-butoxide and 10mmole of 18-crown-6 was stirred in 5 g of p-anisidine under nitrogen at60° C. for 12 hours. 10 ml of 90% methanol was added to homogenize thesolution. A weighted aliquot was sampled for HPLC and was found tocontain 80% of 4-(4methoxyphenylazo)diphenylamine and 19% of azobenzene.

(c) 10 mmole of azobenzene, 20 mmole of potassium t-butoxide and 10mmole of 18-crown-6 was stirred in 5 g of p-chloroaniline under nitrogenat 70° C. for 12 hours. 10 ml of 90% methanol was added to homogenizethe solution. A weighted aliquot was sampled for HPLC and was found tocontain 31% of 4-(4-chlorophenylazo)diphenylamine, 38% of hydrazobenzeneand 30% of azobenzene.

(d) 10 mmole of azo benzene, 20 mmole of potassium t-butoxide and 10mmole of 18-crown-6 was stirred in 5 g of p-toluidine under nitrogen at80° C. for 12 hours. 10 ml of 90% methanol was added to homogenize thesolution. A weighted aliquot was sampled for HPLC and was founds tocontain 60% of 4(tolylphenylazo)diphenylamine and 40% of azobenzene.

(e) 10 mmole of azobenzene, 5 g of p-nitroaniline, 20 mmole of potassiumt-butoxide and 10 mmole of 18-crown-6 was stirred in 4 ml of DMSO undernitrogen at 100° C. for 72 hours. 10 ml of 90% methanol was added tohomogenize the solution. A weighted aliquot was sampled for HPLC and wasfound to contain 23% of 4-(nitrophenylazo)diphenylamine and 74% ofazobenzene.

(f) 10 mmole of azobenzene, 2 g of 1,4-phenylenediamine, 20 mmole ofpotassium t-butoxide and 10 mmole of 18-crown-6 was stirred in 4 ml ofDMSO under nitrogen at 100° C. for 72 hours. 10 ml of 90% methanol wasadded to homogenize the solution. A weighted aliquot was sampled forHPLC and was found to contain 90% of 4-(aminophenylazo)diphenylamine.

Example 17

This example illustrates the production of 4-(phenylazo)diphenylaminefrom the reaction of aniline and azobenzene.

75 ml of 25% aqueous tetramethylammonium hydroxide was evaporated todryness at 60° C./20 mmHg followed by addition of 18.5 gm of azobenzeneand 75 ml of aniline. The solution was stirred at 60° C./20 mmHg for 4hours, approximately 30 ml of aniline was distilled, then 50 ml of waterwas added. The aniline solution was assayed to contain 99% yield of4-(phenylazo)diphenylamine and 6% of N-methylaniline by HPLC based onazobenzene.

Example 18

This example illustrates the production of 4-(phenylazo)diphenylamineunder aerobic conditions.

A solution of 25% aqueous tetramethylammonium hydroxide (8 mL) wasconcentrated under vacuum at 75° C. until solid material formed.Azobenzene (1.8 g) and aniline (10 mL) were added and the solution wasstirred under the same conditions for 4 hours and then in the presenceof air for 12 hours. Analysis of the reaction by HPLC revealed 90% yieldof 4-(phenylazo)diphenylamine.

Example 19

This example illustrates the conversion of 4-(phenylazo)diphenylamine to4-aminodiphenylamine using isoamyl alcohol as the protic material.

A solution of 4-(phenylazo)diphenylamine (2.73 g), isoamyl alcohol (0.08g), potassium t-butoxide (0.22 g) and 18-crown-6 (1.3 g) was heatedbetween 100°-120° C. under nitrogen for 12 hours. The yield of 4-ADPAwas 80%.

Example 20

This example illustrates the production of 4-ADPA from the aerobicreaction of aniline and base forming azobenzene in-situ.

Aniline (0.9 g) and potassium t-butoxide (2.2 g) was stirred in 5 g oft-butanol at 80° C. in air for 12 hours. An aliquot was taken out forHPLC analysis which revealed a 30% yield of 4-ADPA and a 70% yield ofazobenzene based on aniline charges.

That which is claimed is:
 1. A process for preparing substitutedaromatic amines comprising:(a) contacting a nucleophilic compoundselected from the group consisting of aniline, substituted anilinederivatives, aliphatic amines, substituted aliphatic amine derivativesand amides with a substituted aromatic azo compound or azoxy or hydrazoderivatives thereof in the presence of a suitable solvent system, and(b) reacting the nucleophilic compound and the substituted aromatic azocompound or azoxy or hydrazo derivatives thereof in the presence of asuitable base and a controlled amount of protic material at a reactiontemperature of about 70° C. to about 200° C., wherein the molar ratio ofprotic material to base is 0:1 to about 5:1, wherein the substitutedaromatic azo compound is selected from the group consisting of compoundsrepresented by the formula ##STR11## compounds represented by theformula ##STR12## compounds represented by the formula ##STR13## andmixtures thereof, wherein R--NH--represents a substituent derived from acompound selected from the group consisting of aniline, substitutedaniline derivatives, aliphatic amines, substituted aliphatic aminederivatives and amides, R₁ is an aromatic group, R₂ is selected from thegroup consisting of aliphatic and aromatic groups, and X and Y areindependently selected from the group consisting of hydrogen, halides,--NO₂, --NH₂, aryl groups, alkyl groups, alkoxy groups, sulfonategroups, --SO₃ H, --OH, --COH, --COOH, and alkyl, aryl, arylalkyl oralkylaryl groups containing at least one --NH₂ group, wherein halidesare selected from the group consisting of chlorine, bromine and fluorineand R₂ is an aromatic group in substituted aromatic azo compounds (II)and (III).
 2. The process of claim 1 wherein the substituent of saidsubstituted aniline derivatives is selected from the group consisting ofhalides, --NO₂, --NH₂, alkyl groups, alkoxy groups, sulfonate groups,--SO₃ H, --OH, --COOH and aryl, arylalkyl or alkylaryl groups containingat least 1 --NH₂, group wherein halides are selected from the groupconsisting of chloride, bromide and fluoride.
 3. The process of claim 2wherein said substituted aniline derivatives are selected from the groupconsisting of 2-methoxyaniline, 4-methoxyaniline, 4-chloroaniline,p-toluidine, 4-nitroaniline, 3-bromoaniline, 3-bromo-4-aminotoluene,p-aminobenzoic acid, 2,4-diaminotoluene, 2,5-dichloroaniline,1,4-phenylenediamine, 4,4'-methylene dianiline and1,3,5-triaminobenzene.
 4. The process of claim 1 wherein said amide isselected from the group consisting of aromatic amides, aliphatic amides,substituted aromatic amide derivatives, substituted aliphatic amidederivatives and diamides having the formula: ##STR14## wherein R₄ and R₅are independently selected from the group consisting of aromatic groups,aliphatic groups and a direct bond, and A is selected from the groupconsisting of ##STR15## --SO₂ --, --O--, --S-- and a direct bond.
 5. Theprocess of claim 4 wherein said aliphatic amides and said substitutedaliphatic amide derivatives are represented by the formula: ##STR16##wherein n is 0 or 1, R₃ is selected from the group consisting of alkyl,aryl alkyl, alkenyl, arylalkenyl, cycloalkyl and cycloalkenyl groups andX is selected from the group consisting of hydrogen, --NOR₂, --NH₂, arylgroups, alkoxy groups, sulfonate groups, --SO₃ H, --OH, --COH, --COOH,and alkyl, aryl, arylalkyl or alkylaryl groups containing at least one--NH₂ group.
 6. The process of claim 5 wherein said aliphatic amides andsaid substituted aliphatic amide derivatives are selected from the groupconsisting of isobutyramide, urea, acetamide and propyl amide.
 7. Theprocess of claim 4 wherein the substituent of said substituted aromaticamide derivatives is selected from the group consisting of halides,--NO₂, --NH₂, alkyl groups, alkoxy groups, sulfonate groups, --SO₃ H,--OH, --OH, --COOH and alkyl, aryl, arylalkyl or alkylaryl groupscontaining at least one --NH₂ group, wherein halides are selected fromthe group consisting of chloride, bromide and fluoride.
 8. The processof claims 7 wherein said aromatic amides and said substituted aromaticamide derivatives are selected from the group consisting of benzamide,4-methylbenzamide, 4-methoxybenzamide, 4-chlorobenzamide,2-methylbenzamide, 4-nitrobenzamide, and 4-aminobenzamide.
 9. Theprocess of claim 1 wherein said diamides are selected from the groupconsisting of adipamide, oxalic amide, terephthalic diamide, and4,4'-biphenyldicarboxamide.
 10. The process of claim 1 wherein saidaliphatic amine and said substituted aliphatic amine derivatives arerepresented by the formula X'--R₆ --NH--R₇ --Y' and compoundsrepresented by the formula: ##STR17## wherein R₆ is selected from thegroup consisting of alkyl, alkenyl, cycloalkyl and cycloalkenyl groups,R₇ is selected from the group consisting of a direct bond, alkyl,alkenyl, cycloalkyl and cycloalkenyl groups, R₈ and R₉ are independentlyselected from the group consisting of alkyl and alkenyl groups, Z isselected from the group consisting of a direct bond, --NH--, --N(R₁₀)--,--O--and --S--, wherein R₁₀ is an alkyl group, and X' and Y' areindependently selected from the group consisting of hydrogen, halides,--NO₂, --NH₂, aryl groups, alkoxy groups, sulfonate groups, --SO₃ H,--OH, --COH, --COOH, and alkyl, aryl, arylalkyl or alkylaryl groupscontaining at least one --NH₂ group, wherein halides are selected fromthe group consisting of chloride, bromide and fluoride.
 11. The processof claim 10 wherein said aliphatic amine and said substituted aliphaticamine derivatives are selected from the group consisting ofcyclohexylamine, 2-butylamine, isopropylamine, 2-hexylamine,2-heptylamine, 1,4-dimethylpentylamine, 1-methylheptylamine,1-ethyl-3-methylpentylamine, 1,3- dimethylbutylamine, octylamine,peperidine, piperazine, hexamethylenediamine, 2-amino-1-propanol,2-amino-1-butanol and 6-aninohexanoic acid.
 12. The process of claim 1wherein said substituted aromatic azo compound is4-phenylazodiphenylamine.
 13. The process of claim 1 wherein saidsuitable solvent system includes a solvent selected from the groupconsisting of aniline, dimethylsulfoxide, dimethylformamide,N-methyl-2-pyrrolidone, pyridine, ethyleneglycoldimethyl ether,diisopropylethylamine, moltenbenzamide and mixtures thereof.
 14. Theprocess of claim 13 wherein said suitable solvent system includes aprotic solvent.
 15. The process of claim 1 wherein said suitable base isselected from the group consisting of organic and inorganic bases. 16.The process of claim 15 wherein said organic and inorganic bases areselected from the group consisting of alkali metals, alkali metalhydrides, alkali metal hydroxides, alkali metal alkoxides, phasetransfer catalysts in conjunction with a base source, amines, crownethers in conjunction with a base source, alkyl magnesium halides, andmixtures thereof.
 17. The process of claim 1 wherein said base isselected from the group consisting of an arylammonium, alkylammonium,aryl/alkylammonium and alkyldiammonium salt in conjunction with a basesource.
 18. The process of claim 1 wherein said nucleophilic compound isaniline and said substituted aromatic azo compound is4-(phenylazo)-diphenylamine.
 19. The process of claim 8 wherein saidsolvent is aniline and said base is selected from the group consistingof potassium hydroxide, potassium t-butoxide, tetraalkylammoniumhydroxide and alkyl substituted diammonium hydroxide.
 20. The process ofclaim 1 wherein said nucleophilic compound and said substituted aromaticazo compound are reacted under aerobic conditions.
 21. The process ofclaim 1 wherein said nucleophiiic compound is selected from the groupconsisting of aniline, substituted aniline derivatives, aliphatic aminesor substituted aliphatic amine derivatives having the formula X'--R₆--NH₂, and amides and said substituted aromatic azo compound are reactedunder anaerobic conditions wherein R₆ is selected from the groupconsisting of alkyl, alkenyl, cycloalkyl and cycloalkenyl groups and X'is selected from the group consisting of hydrogen, halides, --NO₂,--NH₂, aryl groups, alkoxy groups, sulfonate groups, --SO₃ H, --OH,--COH, --COOH, and alkyl, aryl, arylalkyl or alkylaryl groups containingat least one --NH₂ group wherein halides are selected from the groupconsisting of chloride, bromide and fluoride.
 22. The process of claim 1wherein a desiccant is present during step (b) to control the amount ofprotic material present during the reaction of said nucleophiliccompound and said substituted aromatic azo compound.
 23. The process ofclaim 1 wherein the amount of protic material in step (b) is controlledby the continuous distillation of said protic material.
 24. The processof claim 1 wherein said nucleophilic compound is an amide furthercomprising:(c) reacting said substituted aromatic amine with ammoniaunder conditions which produce a corresponding substituted aromaticamine and amide.
 25. The process of claim 24 further comprising:(d)reductively alkylating the substituted aromatic amine of (c).
 26. Aprocess for preparing 4-aminodiphenylamine (4-ADPA) or, substitutedderivatives thereof comprising:(a) contacting aniline or substitutedaniline derivatives and 4-(phenylazo)-diphenylamine or substitutedderivatives thereof in the presence of a suitable solvent system, and(b) reacting the aniline or substituted aniline derivatives and4-(phenylazo)-diphenylamine or substituted derivatives thereof in thepresence of a suitable base and a controlled amount of protic materialat a reaction temperature of about 70° C. to about 200° C. in a confinedreaction zone, wherein the molar ratio of protic material to base is 0:1to about 5:1.
 27. The process of claim 26 further comprising:(c)reductively alkylating the 4-aminodiphenylamine or substitutedderivatives thereof.
 28. The process of claim 1 further comprising:(c)reductively alkylating the substituted aromatic amine of (b).